In vehicles which are equipped with a servo steering system such as, e.g., electric servo steering, on the basis of a torque exerted on the steering wheel by the driver there is produced a supporting torque which decreases the effort required for steering and so increases the driving comfort. The supporting torque can have superimposed on it a return torque which serves to support the natural restoring movement of the wheels towards the neutral position straight ahead, and so make it easier to keep to the lane during driving. The amount of the return torque is usually predetermined by a return torque signal which is generated by a control device. With known servo steering systems, the return torque signal is, for example, generated as a function of the current steering wheel position and the current vehicle speed.
A return torque determined in this way may, however, be disadvantageous in certain driving situations. If, for example, the vehicle is accelerated during a restoring operation, then the natural restoring force increases and the movement of the steering wheel towards the neutral position may increase undesirably quickly. Conversely, at low speeds the return torque may be too low to maintain the restoring movement or set it in motion. Further, usually a high return torque is necessary with low steering angles, because here the automatic restoring force is small. If, however, the driver performs steering maneuvers within this range around the neutral position, then a rigid steering feel or undesirably quick restoring movement of the steering wheel may occur.